1. Field of the Invention
This invention relates to synthetic intermediate compounds useful in preparing color photosensitive materials. More particularly, it relates to intermediate compounds for producing compounds which release a diffusible dye by a redox reaction subsequent to development of silver halide.
2. Description of the Prior Art
A color diffusion transfer image-forming process which comprises using dye-releasing redox compounds (also often referred to as DRR compounds) has been described in Japanese Patent Application (OPI) No. 33826/73 (the term "OPI" as used herein refers to a "published unexamined Japanese patent application"). The expression "dye-releasing redox compounds" used above is p-sulfonamidophenols (or p-sulfonamidonaphthols) in which a dye part and a nondiffusible phenol part (or naphthol part) are linked at the p-position (with respect to the aromatic --OH group) through a sulfonamido group. When a photosensitive silver halide emulsion coexistent with said compound is exposed to light and developed thereafter, the p-sulfonamidophenol or naphthol is oxidized corresponding to the developed silver halide content. It has been presumed that the resulting oxidation product is decomposed by attack of alkali processing solution to form a diffusible dye and nondiffusible benzoquinone or naphthoquinone, and that the resulting diffusible dye is transferred to an image-receiving layer. However, when using the above-described p-sulfonamidophenols, their dye-releasing efficiency is so low as to produce a sufficient transfer density. Furthermore, the above-described p-sulfonamidonaphthols produce yellow stains, because some p-naphthoquinone is left at the photosensitive layer side, even if a desilvering treatment is carried out after releasing the dye, and, consequently, residual color images on the photosensitive layer cannot be utilized as negative or positive images.
Dye-releasing redox compounds which are o-sulfonamidophenols substituted by an alkoxy group on the 4-position thereof have been described in Japanese Patent Application (OPI) No. 113624/76. These compounds have rather excellent properties as compared with the earlier prior art compounds, but it has been desired to further improve the dye-releasing ability of sulfonamidophenols. Also, dye-releasing redox compounds which are o-sulfonamidophenols having an alkoxy group at the 5-position and a methyl group at the 4-position have been described in Japanese Patent Application (OPI) No. 149328/78. However, it has been desired to further improve the dye-releasing ability of these sulfonamidophenols also.